let buffer = new ArrayBuffer(2);//2个字节的ArrayBuffer
console.log(buffer.byteLength);//2
let dataView = new DataView(buffer);
dataView.setInt8(0,1);
dataView.setInt8(1,2);
console.log(dataView.getInt8(0));//1
console.log(dataView.getInt8(1));//2
console.log(dataView.getInt16(0));//? 取一个二个字节(16位的整数)
console.log(dataView.buffer===buffer);
// DataView和TypeArray都 内部引用了buffer